Arrangement For Stabilising Supporting Structures

ABSTRACT

The invention relates to an arrangement for stabilizing supporting structures for equipment, plants, buildings and other construction works. It serves simultaneously for bracing corresponding structures and stabilizing them against vibrations, in particular those that are caused by earthquakes. 
     For this purpose, supporting elements that are adjacent to one another will be braced together by means of tension elements, such as tension cables, tension rods or beam ties, wherein, according to the invention, at least one uniaxially acting additional element, which is formed as a parallel connection between at least one spring and at least one viscous or viscoelastic damper, is disposed in between the tension elements. The tension elements, which brace the supporting elements to one another and the one or more additional elements disposed in between them form a stabilizing unit according to the invention, within which the tension elements and the one or more additional elements are connected to one another in series. According to the invention, a prestressing is produced for the tension elements by means of the additional elements.

The invention relates to an arrangement for stabilizing supportingstructures for equipment, plants, buildings and other constructionworks. The proposed arrangement thus serves simultaneously for bracingcorresponding structures and stabilizing them against vibrations, inparticular those that are caused by earthquakes. Preferably, thearrangement according to the invention serves for stabilizing framingconstructions.

It has been known for a long time, in particular in the building trade,to statically stabilize supporting structures, such as framingstructures, for example, of tall buildings, by bracing elements, wherebythe appropriate bracing elements bring about a load reduction of thestructure. Here, the so-called “support triangle” or the bracing offraming structures by means of diagonally disposed bracings, which areincorporated load-free in a corresponding supporting structure, isparticularly familiar. It is also known to stabilize tall buildings,such as steel towers, for example, by tension cables or tension rods.The above-named measures are very effective, in fact, with respect tothe static stabilization of the most varied supporting structures andare indispensable in many cases, but they are effective only withlimitations in the case of dynamic loads that may occur, such as arecharacteristic in the case of intense vibrations caused by earthquakes.At least, it is not possible with these measures to provide a uniaxialstabilization against dynamic loads or the stabilization of a structuralelement such as, for example, an element of a framing structure, withonly one frame brace. Rather, in order to obtain a certain stabilizationeffect against dynamic loads, it is necessary to arrange appropriatebracing elements such as beam ties, for example, in pairs and orientedin opposite directions to one another. An appropriate arrangement thatreproduces this prior art is shown, for example, by FIG. 9. A comparablesolution is also disclosed by U.S. Pat. No. 6,233,884 B1.

With respect to the protection of construction works against vibrationsas caused by earthquakes, the use of dampers, particularly viscousdampers, has been proposed in different ways in the past. An appropriatesolution employing a damper inserted diagonally into a framing structureis disclosed, for example, by WO 01/73238 A2. The solution that isshown, however, is associated with the disadvantage that it must bedesigned very solidly or massively due to the alternating tensile andcompressive loads, as are typical in practice, particularly in the caseof earthquakes, in order to minimize the danger of buckling that existswith compressive loads for dampers or for fastening elements of thedamper or the connection elements, respectively, given their structure.This requirement of a sturdy or massive design is accompanied byrelatively high costs when the named solution is employed. In addition,the damper does not contribute to the static reinforcement of thesupporting structure. Rather, for this purpose, as can be seen from FIG.5 of the named document, special bracing elements are disposed on thesupporting structure, for example, in other frames of a framingstructure.

The object of the invention is to provide a solution that makes possiblean effective, yet cost-favorable stabilizing of supporting structuresboth from a static as well as a dynamic perspective.

The object is solved by an arrangement with the features of theprincipal claim. Advantageous embodiments or enhancements of thearrangement of the invention are given by the subclaims.

The arrangement according to the invention serves for stabilizingsupporting structures for technical objects, such as equipment, plants,buildings or other construction works. Supporting structures thatconsist of supporting elements that are formed as supports or horizontalsupporting girders and/or form a framing structure, will be stabilizedwith it. Thus, in a way known in and of itself, supporting elements thatare adjacent to one another will be braced together by means of tensionelements, such as tension cables, tension rods or beam ties. Accordingto the invention, however, at least one uniaxially acting additionalelement that is formed as a parallel connection between at least onespring and at least one viscous or viscoelastic damper is disposed inbetween the tension elements. The tension elements which brace thesupporting elements with one another and the one or more additionalelements disposed in between them form a stabilizing unit according tothe invention. The tension elements and the one or more additionalelements are connected to one another in series within the stabilizingunit that is formed in this way. In a way that is essential to theinvention, a prestressing is produced for the tension elements by meansof the additional elements. In this way, the stabilizing unit forms astatic reinforcement for the supporting structure, but it also acts in aload-reducing manner, even in the case of strong dynamic loads, forexample, due to vibrations that are caused by earthquakes. Byprestressing the cables or beam ties, compressive forces do not arise inthe stabilizing unit under the effect of earthquakes. The damping andthe spring rigidity of the stabilizing unit formed by the arrangementaccording to the invention thus are effective also in the case ofalternating stresses (alternating between tensile and compressivestresses) in an advantageous manner, since only the static tensile forceis increased or decreased by the earthquake forces. Expensive or other,additional compressive reinforcements that prevent a buckling of thestabilizing unit under pressure are usually not necessary. At the sametime, the prestressing of the tension elements causes the rigidity orloading capacity of the stabilizing unit to contribute to removing theloads caused by earthquake forces. Therefore, the unit also serves for(static) reinforcement. The damping of the system as well as itsresistance will be effectively increased in order to take up earthquakeforces.

The spring or springs of the additional element disposed in between thetension elements may involve screw-type pressure springs according toone possible embodiment of the invention. A tension element and anadditional element are coupled by means of a coupling element loadedwith the compressive force of the screw-type pressure spring or springs,which deflects this compressive force and transfers it to the tensionelement as tensile force.

The spring or springs of the additional element, however, may also bedesigned as a tension spring, whereby a tension element and thisadditional element are then coupled by a coupling element, by means ofwhich the tensile force of the tension spring or springs that acts onthese springs is transferred almost directly to the tension element.

With respect to the joining of the stabilizing unit, there are also manydifferent possibilities in the sense of the arrangement according to theinvention. For example, the stabilizing unit can join together thesupporting elements of a framing structure. According to one possibleconfiguration that is relevant in practice, a diagonal reinforcement forthe frames of a framing structure is thus formed by the stabilizingunit, wherein the stabilizing unit preferably joins together two cornerpoints of the frame.

The arrangement according to the invention, however, can also be formedin such a way that the supporting elements that are adjacent to oneanother, which are joined together by means of a stabilizing unit,involve parts of supporting structures of different technical objects,thus, for example, supports of the framing structures of two buildingsthat are adjacent to one another.

The invention will be explained once more in more detail below on thebasis of embodiment examples. In the appended drawings are shown:

FIG. 1A schematic representation of a first embodiment of thearrangement according to the invention

FIG. 2 The schematic representation of another possible embodiment

FIGS. 3-5 Modifications of the embodiments explained above orpossibilities for their combination

FIGS. 6-8 Possibilities for joining the arrangement according to theinvention to supporting structures

FIG. 9 The schematic representation of an arrangement for the bracing ofsupporting structures according to the prior art.

FIG. 10 The schematic representation of a solution known from the priorart for stabilizing construction works against vibrations caused byearthquakes.

FIGS. 1 and 2 each show, in schematic representation, possibleembodiments of the arrangement according to the invention. These arecontrasted to the arrangements which are also shown schematically inFIGS. 9 and 10, and which are known from the prior art, on the one hand,for the static stabilization of construction works, and, on the otherhand, for their protection against vibrations caused by earthquakes. Forbetter clarification of the effect obtained with the arrangementaccording to the invention, arrangements known from the prior art, whichare sketched in FIGS. 9 and 10, will first be discussed briefly. FIG. 9shows schematically a supporting structure 7 formed as a framingstructure 10, which is statically stabilized by diagonally disposedreinforcing elements 11, 11′, for example, corresponding braces. As wasalready emphasized initially, arrangements such as these, in which thebraces are inserted free of load into the supporting structure, haveproven suitable for static stabilization. As far as intercepting dynamicstresses is concerned, however, it is not sufficient to stabilize such aframing structure 10 by means of only one reinforcing element 11 actinguniaxially. Rather, as shown in FIG. 9, it is necessary to arrangecorresponding reinforcing elements 11, 11′ in pairs and to arrange themoriented in opposite directions to one another. However, even with thismeasure, only a comparatively small protection is afforded againstdynamic vibrations, for example, those caused by earthquakes.

FIG. 10 shows schematically an arrangement for the dynamic stabilizationof a construction work or the like, as it is known from the prior artcited initially. A preferably viscous or viscoelastic damping element 12is incorporated in an essentially diagonal arrangement in a supportingstructure 7 also formed as a framing structure 10. A staticallyreinforcing effect, however, is not provided by such a damping element12. In order to achieve a sufficient stability against stressesalternating between tensile and compressive stresses, which areaccompanied by an elevated danger of buckling, particularly in the caseof compressive stress, a very sturdy or massive design of the dampingelement 12 is necessary. The damping element 12 that is shown does notcontribute to diverting the static forces caused by the structureitself, so that special reinforcing elements must be provided for thispurpose.

In contrast to this, an effective stabilization of supporting structures7, 7′ simultaneously under both static as well as dynamic stresses isachieved by the solution according to the invention, as it is shown inFIGS. 1 and 2 in two possible variants. Therefore, the arrangement alsopossesses a very simple form, which makes it cost-effective for itsmanufacture and installation, on the one hand, and, on the other hand,allows it to be adapted very simply to different special features andrequirements; it also can be retrofitted, for example, for existingconstruction works or support systems for equipment. The basic principleaccording to the invention is common to both variants. Accordingly, astabilization of the structure is produced by means of tension elements1, 1′, such as beam ties or tension rods, in between which are disposeda viscoelastic additional element 2, 2′, i.e., in parallel, a spring 3,3′ and a viscous or viscoelastic damper 4, wherein the tension elements1, 1′ are prestressed by means of the additional element 2, 2′. The twoschematically shown variants differ to the extent that in the designaccording to FIG. 1, a tension spring 3 is used, whereas in the variantaccording to FIG. 2 a screw-type pressure spring 3′ is used.Consequently, the viscoelastic additional element 2, 2′ disposed inbetween the tension cables or tension rods 1, 1′ is coupled in differentways, as can be seen from the figures. According to the variant of FIG.1, the additional element 2 and the tension elements 1, 1′ are joinedtogether by coupling elements 5, 6, which transmit the tensile force ofthe tension spring to the tension elements almost directly. In contrast,the coupling elements 5′, 6′ in the embodiment according to FIG. 2 actin a force-deflecting manner, by transmitting the compressive force,with which they are loaded by the pressure spring 3′, as a tensile forceto the tension elements 1, 1′, which determines the prestressing of thetension elements 1, 1′. In the given representations of the invention,the reference numbers 3 und 3′ as well as the reference number 4 thusrefer also, optionally, to groups of springs 3, 3′ or dampers 4 disposedin parallel, wherein appropriate groups with suitable geometry adaptedto one another are employed in practice.

According to the invention, the arrangement that serves for stabilizinga supporting structure 7, 7′ is configured in such a way that at leastone viscoelastic additional element 2, 2′ is disposed in between thetension elements 1, 1′ bracing adjacent supporting elements 8, 9, 9′,10, 10′ of the supporting structure 7, 7′, and is connected to them inseries with the formation of a stabilizing unit. This, of course, leavesopen the possibility that several viscoelastic additional elements 2, 2′are disposed within one stabilizing unit. Optionally, the variants forthe connection between tension elements 1, 1′ and additional elements 2,2′, which are shown in FIGS. 1 and 2, may also be combined with oneanother. Appropriate possibilities are illustrated by FIGS. 3 to 5.

Likewise, just as the respective layout of the components of thearrangement according to the invention, for example the size andthickness of the beam ties 1, 1, 1′, the prestressing force or thespring constant of the spring or springs 3, 3′ of the viscoelasticadditional element 2, 2′ or the dimensioning of its damper 4 depend onthe respective special features, such as type of supporting structure 7,7′ and site of installation, as well as the loads that are anticipated,different possibilities or requirements for the type and manner ofinstallation of the arrangement and its connection with the principalsystem of the one or more supporting structures 7, 7′ are applied as afunction of the named factors. As an example of this are thepossibilities shown schematically in FIGS. 6 to 8, but these are not tobe considered the only possibilities.

FIGS. 6 and 7 show two possibilities for a diagonal connection of thearrangement according to the invention with the supporting elements 8,9, 9′ of a supporting structure 7 in the form of a framing structure 10;these are distinguished by the selection or positioning of theconnection points between supporting structure 7 and the stabilizingunit. Whereas the stabilizing unit formed from the beam ties and theadditional elements 2, 2′ corresponding to FIG. 6 connects two cornerpoints of the frame of a framing structure 10, according to FIG. 7, itis bound to the lengthwise sides of two supporting elements 8, 9 of thesupporting structure 7 that are adjacent to one another and connectedwith one another. FIG. 8 shows the example of a horizontal connection ofthe supporting structures 7, 7′ of two different technical objects orframing structures by means of the stabilizing unit formed from tensionelements 1, 1′ and an additional element 2, for example, the connectionof two towers or poles or one tower with one pole.

In addition to the simple construction and the low costs that result forits use, the arrangement according to the invention has the followingadvantages:

-   -   Due to the fact that alternating stresses (alternating tensile        and compressive stresses) can be taken up by the arrangement,        the furnishing of one reinforcing field or one frame of a        framing structure consisting of a multiple number of grid-like        frames joined together can be sufficient for the earthquake        protection of a system or a technical object such as a building.    -   The stabilizing unit formed from the combination of tension        elements and viscoelastic* (viscoelastic) additional element(s)        can engage in the direct vicinity of the framing nodes and        usually requires no other special * sic; viscous?—Trans. note.        reinforcement, unlike the solutions known from the prior art.    -   The earthquake resistance of the structure is essentially        improved with correct layout.    -   The arrangement can be applied in new construction or for        earthquake resistance of existing structures.    -   The three-dimensional orientation does not play a role with the        use of uniaxially acting dampers. Thus, either a horizontal or        vertical reinforcement of supporting structures can be achieved.    -   The arrangement or the total system is easy to model        dynamically. In actual use, additional static loads occur, which        are frequently found in equilibrium.    -   The arrangement is easy to install—usually, no extensive        additional measures are necessary. The existing support system        or the supporting structure is usually not changed, but only        complemented by additional rigidity and damping.    -   The arrangement operates purely passively—a special input of        energy and a control mechanism are not necessary.    -   The arrangement is nearly maintenance-free and does not wear.    -   A standardizing, for example, for different prestressing forces,        is conceivable.    -   The arrangement can be used in a very versatile manner due to        the above-named advantages.

LIST OF REFERENCE NUMBERS USED

-   1, 1′, 1′ Tension element (tension cable, tension rod, tension strap    or beam tie)-   2, 2′ Additional element-   3 Tension spring-   3′ (Screw-type) pressure spring-   4 Viscous or viscoelastic damper-   5, 6 Coupling element-   5′, 6′ Coupling element-   7, 7′ Supporting structure-   8 Girder-   9, 9′ Supports-   10, 10′ Framing structure-   11 Reinforcing element-   12 Damper

1. An arrangement for stabilizing supporting structures for technicalobjects, such as equipment, plants, buildings or other constructionworks, whose supporting structures consist of supporting elements, whichare formed as supports or horizontal support girders and/or form aframing structure, wherein supporting elements that are disposedadjacent to one another are braced together by means of tensionelements, such as tension cables, tension rods or beam ties ischaracterized in that at least one uniaxially acting additional elementthat is formed as a parallel connection between at least one spring andat least one viscous or viscoelastic damper is disposed in between thetension elements and the tension elements that brace the supportingelements to one another and the one or more additional elements thatis/are disposed in between them form a stabilizing unit, within whichthe tension elements and the one or more additional elements areconnected to one another in series, and a prestressing of the tensionelements is produced by means of the additional elements, so that astatic reinforcement for the supporting structure is formed by thestabilizing unit, which also acts to reduce the load in the case ofstrong dynamic stress, for example, caused by earthquakes.
 2. Thearrangement according to claim 1, further characterized in that thespring or springs of an additional element are formed as screw-typepressure springs, wherein the coupling between a tension element andthis additional element is provided by a coupling element loaded withthe compressive force of the screw-type pressure spring or pressuresprings, and this element deflects this compressive force and transfersit as tensile force to the tension element.
 3. The arrangement accordingto claim 1, further characterized in that the spring or springs of anadditional element are formed as tension springs, wherein the couplingbetween a tension element and this additional element is provided by acoupling element, by means of which the tensile force of the tensionspring or tension springs acting on it is transferred to tensionelement.
 4. The arrangement according to one of claims 1 to 3, furthercharacterized in that the stabilizing unit connects the supportingelements of a framing structure with one another.
 5. The arrangementaccording to claim 4, further characterized in that a diagonalreinforcement for the frames of a framing structure is formed by thestabilizing unit.
 6. The arrangement according to claim 5, furthercharacterized in that the stabilizing unit connects two corner points ofthe frame of a framing structure with one another.
 7. The arrangementaccording to one of claims 1 to 3, further characterized in that thesupporting elements that are adjacent to one another and which areconnected to one another by means of a stabilizing unit that is formedfrom tension elements and additional elements involve parts ofsupporting structures of different technical objects.